


Mercedes' Secret Ingredient

by SerketsReign



Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Ass Expansion, Breast Expansion, Breast Growth, Butt Expansion, Dominance, Domination, F/F, F/M, Fire Emblem - Freeform, Garreg Mach, Grinding, Humor, Kissing, Large Breasts, Muscle Growth, NSFW, Romance, School, Sex, Smut, Three Houses, black eagle - Freeform, blue lion - Freeform, boobs, butt growth, expansion, f/f - Freeform, f/m - Freeform, female muscle growth, pre timeskip, relationship
Language: English
Status: In-Progress
Published: 2020-10-05
Updated: 2021-01-13
Packaged: 2021-03-07 17:13:54
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 8,354
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26831212
Author URL: https://archiveofourown.org/users/SerketsReign/pseuds/SerketsReign
Summary: Back from the ether with a Three Houses expansion fic. Mercedes shows Annette the secret to how she got her figure — and how to get it herself
Relationships: Annette Fantine Dominic/Linhardt von Hevring, Annette Fantine Dominic/Mercedes von Martritz, Ingrid Brandl Galatea/Sylvain Jose Gautier
Comments: 5
Kudos: 29





	1. Annette's Grow-Up

“Ah, glad you could make it tonight, Annette!” Mercedes said as she opened the door for her lifelong friend.

“Thanks for inviting me, Merce! I’m really excited for our sleepover!” Annette stepped inside and threw off her coat once she was in the warm, cozy room.

She was wearing loose-fitting pajama pants and a tank top that hugged her slim frame. Mercedes had on a pair of short shorts that hugged her wide hips, and wore a baggy shirt that did little to bely her large breasts. As she had many times before, Annette found herself with a twinge of jealousy at her friend’s curvaceous body. She’d hoped that the years would give her a more womanly figure, only to be disappointed as time went on.

“So, Annette, I wanted to share something with you. I’ve wanted to show you this for a long time, actually.”

“Oh!” Annette’s eyes shot back up to her friend’s face and she realized she’d been staring at her chest quite blatantly. “What is it?”

“You know Annette, I didn’t always look this way.”

"What do you mean?”

Mercedes giggled.

“Well, I didn’t always have these.” Mercedes cupped her hands around her breasts and gave them a bounce. “You could say I was a bit... flat chested.” Mercedes then ran her hands down along the curves of her slim waist and generous hips. “And I had the shapliness of a stick.”

Annette’s face grew bright red at Mercedes’ incredibly straightforward display. She opened her mouth but closed it, and let her continue.

“What is it, Annie? I see you staring quite a bit, and I wanted to help you out.”

“H-help me out, how?” Annette found herself quite flustered. “I don’t know what you mean.”

Mercedes beamed.

“Sure you do! I know you have eyes for a certain someone. This will help you catch his eye.”

“Er…..”

Mercedes opened a drawer and pulled out a small, handsome box. Inside were rows of small glass bottles, each with a frothy golden liquid inside, though one was missing. There were seven total. Mercedes gingerly wriggled one out of the velvet they were nestled in and handed it to Annette.

“Careful, these were quite hard to come by. I only took one of them a few years ago and it really did the trick. You should try it!

“So if I drink this, it’ll…”

“It’ll make you even more of a looker than you are now,” Mercedes said with a wink.

“I don’t know Merce, what if people notice and ask questions?”

“Ask them if they like it! Own it! Here, I’ll drink one with you if you want.”

Annette’s heart was racing. She felt as though she shouldn’t, but at the same time felt giddy at the possibilities. She uncorked the glass.

“Well… Bottom’s up!” she said.

The two ladies drank their potions in one gulp. For a moment, Annette felt nothing. Then -

Annette burped loudly and laughed giddily. The potion made her feel warm and bubbly, and she felt as though she could dance all night. Next to her, Mercedes was reacting in a similar fashion.

With another hiccup, Annette noticed Mercedes’ booty shorts seemed to be shrinking. After a double take, she realized that it was the opposite: Mercedes was growing. Her already rather thick thighs were expanding, relegating the small shorts to even less of her shapely legs.

“It’s starting!” Mercedes said with glee. 

Annette looked down at her pajama pants. Hadn’t they been loose before? Now they were anything but as her thighs, hips, and butt grew with surprising speed. Quickly, Annette tugged off her pajamas to see a pair of thick, shapely legs underneath them, straining her underwear. Annette’s hands shot to her previously flat butt, which was now large and round, pushing her beleaguered underwear back even farther. 

There was a ripping sound and Annette turned back to Mercedes, seeing her booty shorts begin to rip. Mercedes turned around to show Annette her incredible new ass, and with a clench of her butt, she ripped apart the shorts in one go. Underneath, Mercedes’ panties made no effort to cover anything, and indeed were almost completely lost beneath her large, perky ass.

Mercedes cupped the bottom of her ass cheeks with her hands, feeling the new firm shape.

“It might be a bit much, but - no - who am I kidding? I love it!” Mercedes kicked out her right leg, showing off her new legs and ass. Annette noticed how much shaplier and thicker her thighs were as well, and saw that her friend had gained an inch or two of height.

Annette looked back in the mirror to see her lower body was completely transformed. Her legs were shapely and well-defined in a way that put even Petra to shame, and her ass jutted out like a shelf from her back. Still, she felt a bit jealous, and downed another potion.

“Annette, I see you like these just as much!” Mercedes said, approving of her friend’s enthusiasm. Annette saw her Mercie’s breasts had swelled even larger, yet somehow looked even perkier. They bulged out of her too-small tank top, straining her poor bra, yet somehow were more firm and lifted than even Annette’s small rack. Mercedes walked sensually over behind Annette, her hips gyrating and huge tits bouncing playfully as she did so, and gave her ass a nice slap as it began to grow again. This time, it was Annette’s turn to make her panties scream for mercy, and soon they were almost completely swallowed by her huge, perfect ass.

Her legs were now incredible, long with feminine muscle underneath curvaceous flesh, the envy of the whole monastery. Her hips were now wide and inviting, much large than her shoulders. Next, Annette noticed her small breasts, which the first potion hadn’t even gotten around to yet, beginning to jut out and grow, quickly filling her tight tank top. Mercedes put a hand over Annette’s right breast even as her own continued to grow, making the shirt she wore stretch out even more.  
In moments, Annette’s breasts were larger than Mercedes’ were, and her tank top was shredding itself to ribbons. No longer covering her belly, all available fabric was spent on keeping Annette’s new melons in check. Her nipples, much larger and more responsive than before, poked visibly out through her bra and tank top, aroused by the stimulation.

And still, her breasts and lower body continued to grow. Annette saw herself shoot up to match Mercedes’ height, then gain another inch or two on her. Mercedes’ face opened in wonder and delight as Annette’s tits finally tore apart the remaining scraps of cloth that held them in place. Despite no longer being supported by a bra, Annette’s breasts were firmer and perkier than they had been when they were small, and bounced happily on her chest. Annette felt around them in shock, in complete awe at the sheer size and shape of them. Just moments ago she’d been tiny, and now…

Mercedes and Annette turned back to the mirror. Gone were the two women of before, who looked like children now. Mercedes had gained a few inches, but Annette stood above her now. Their hips were incredible, wider than their shoulders, and their thighs were thick and shapely, yet had at least three inches between them. Mercedes gave Annette’s ass another slap, and her hand bounced off of her tight asscheecks. Annette checked her friend’s ass, which was just as impressive. Both had utterly swallowed their panties, and the front piece of fabric was the only evidence of them existing. Annette’s torso was flat but firm, and her tits…

The size of melons, they’d somehow grown even larger than Mercedes’. Still, her friend’s were almost as large, and her nipples had grown in size. Annette reached out and cupped one of them in her hands, though they couldn’t begin to hold the full thing.  
Mercedes closed her eyes and let out a soft coo, rubbing her thick thighs together as her knees buckled slightly. 

“Play with them,” she breathed, and Annette began to move her hand around her considerable breasts, squeezing tentatively here and there.

“Both hands…”

Annette obliged, moving her body closer. Mercedes reached her hand behind Annette’s back and pulled her even closer, and began pleasuring herself with her spare hand. They were so close now that Annette’s hands barely had room to move between her own  
tits and Mercedes. 

Mercedes let out a loud moan, and Annette wondered if she should stop, slightly uncomfortable. Then, on a whim, she pushed her body closer into her friend’s, smushing their breasts together. Mercedes pressed her tits into her friends, rubbing them against eachother, and Annette followed suit.

“Oh Annie…”

She felt a hand at her ass again as Mercedes had dropped it down there, exploring the shape and size while they gyrated their powerful bodies against each other.

Annette felt a drip in her panties. She didn’t know what she was doing, or why she was doing it. She had never felt this way towards her friend before, but something about her transformation had awakened a rush of sexual desire in her, and she had to have it fulfilled.  
Inspired, Annette gripped Mercedes’ legs with her hands and pulled them around her waist. Mercedes wasted no time in wrapping them tightly around her and grinding her pelvis against Annette’s. Before, she could never have lifted her friend up like that, but now her powerful new legs supported them both with ease. Annette leaned into a wall and grinded with Mercedes, pushing their massive chests even closer together. She enjoyed the feeling of Mercedes’ powerful legs around her, and the sensation of their breasts and nipples running against one another.

Mercedes moved her head in and began to kiss her aggressively, her breath was cool and her lips plump. Annette matched her, moving her mouth around hers. She felt tongue enter her mouth, and gasped as Mercedes’ hand slipped inside her panties.  
Her new body experienced pleasure more intensely than she remembered, and with a rush of orgasmic pleasure she felt her body spasming. She rushed forward, pushing Mercedes onto her bed before her legs gave out, and they resumed their grinding and kissing. Mercedes’ fingers found their way inside her, and she howled with pleasure, unable to move or do anything but focus on the sensation.  
Mercedes sat up, huge tits bouncing playfully as she did, and gave Annette a wink as she licked her lips. She pushed the helpless Annette onto her back, and tore away her soiled panties. Annette felt her huge tits bounce and jostle as their considerable weight fell onto her chest. They obscured a good part of her view, but through them she could see Mercedes wriggle into a better position, getting onto her knees and moving closer to Annette.  
With both hands, Mercie pushed apart Annette’s thighs, rubbing them along the flesh and muscle as she did, and she moved in between them, giving another wink before she plunged her head towards Annette’s groin.

The sensation was indescribable. Mercedes’ lips and tongue moved expertly around, filling her with a voluptuous pleasure. Annette’s whole body buckled and undulated as she moaned uncontrollably, calling out her friend’s name. She arched her back and stamped her feet, hands tightly squeezing her huge tits as the pleasure became overwhelming.

A veritable river of fluid rushed out of her. Mercedes let it run over her, mouth open and tongue hanging out as she stared up at Annette. She lost all sensation except for that sensation, letting it take her as it rolled through her body. 

Some time later, Annette could start to think again. She peered up at the ceiling from an unfamiliar bed.

“Where am I…?”  
“Right where I left you, Annie.” Mercie stood over her, confident in her nudity. Annette stared at her tits, legs, and hips in confusion before it came back to her. In a panic, afraid to believe it could be true, Annette looked down as she rushed her hands to her chest, but her body had retained the changes.

She sat up, drinking in her new body. She still felt aftershocks of pleasure, and rubbed her thighs together on the bed.

“That was... That was incredible Mercie. In more ways than one.”

“I’m so happy you liked it! And I know a few ways you can make it up to me..."


	2. A Midnight Stroll

**Summary for the Chapter:**

> Annette, fresh from her encounter with Mercedes, faces the challenge of making it back to her room unnoticed. (Un)fortunately, she encounters a fellow student on a late-night stroll...

Getting back to her dormitory would be quite the affair. Obviously, everything Annette had worn with her had been shredded beyond recognition, and Mercedes didn’t own anything that could begin to cover up their new figures. Annette wound up borrowing a bathrobe of Mercedes’, though it was far too small. Her legs were wholly exposed, and her ass poked out at the edge of the fabric. The material also failed to fully wrap around her considerable chest, and showed off quite a bit of her cleavage. The chill air also had her nipples perked up, and this was clearly visible through the fabric.

_ Cleavage _ . Annette wasn’t used to that word applying to her. Walking back to her room in the cold night, with the initial rush of hormones gone and the scent of sex no longer clouding her mind, she considered whether drinking two of those potions had been the best plan. All of her clothes were useless now! How was she going to get into town to buy more without any to wear? And would they be selling any that fit her proportions? 

Annette wondered how the rest of the class would react when they saw her and Mercie. Confusion and shock, probably, but Sylvain likely wouldn’t look a gift horse in the mouth. Mercie would certainly wear her looks with confidence, but Annette wasn’t sure if she…

“Annette? Is that you?”

Not him! Anyone but him!

“Eep! No!”

Annette bolted down the street, only to immediately trip and fall over a stack of barrels.

“Who put these stupid barrels here?” Annette tried to get up, but as soon as she put her weight on a barrel, it rolled away, and she hit the cobblestones.

“That certainly proves it. Who else could be so clumsy?”

Annette recognized the slow and somewhat pompous voice even as Lindhardt’s face came into view. She realized that she was exposed and shrieked, attempting to cover her chest with her hands.

“Relax Annette, I’m not the Death Knight.” Lindhardt didn’t so much as flinch at the site of her indecency. “I’m just out on a midnight walk. I might even ask what you’re doing up.” 

“Don’t look at me, my robe fell off!”

Lindhardt peered down at her exposed breasts. “Oh, is  _ that _ what you’re making that fuss for?”

He reached out his hand to help her up. Annette reached out her hand, but this act left her chest exposed again. She yelped and threw her arms tightly over her breasts, causing them to spill over.

Lindhardt sighed and made a show of covering his eyes with his free hand.

“Better?”

Annette accepted his help and he pulled her to her feet. Still exposed, she quickly pulled the bathrobe tight and hugged herself with her arms to keep it shut. Unfortunately, this had the effect of pushing her breasts up and closer together, making her considerable cleavage even more prominent. They were so big she didn’t know what to do with them. She made a sour face and begrudgingly thanked Linhardt for the help.

“Am I allowed to open my eyes now?”

“Fine. But no wandering eyes, mister!”

Linhardt opened his eyes and immediately began studying Annette’s body. Annette flushed.

“Hey!”

“You’ve certainly gotten taller. And…” Linhardt made a show of cupping his hands in front of his chest. “Bigger. I’ll admit, it’s not what I thought it’d be doing when we started studying magic, but the results speak for themselves, I suppose.”

Before, he had towered over Annette. Now, he was only a few inches taller than her.

“How do you always talk about everything so frankly?”

“What, was I supposed to pretend to not notice anything different?”

“I guess not…”

“How’d you do it, if you don’t mind me asking?”

“I didn’t do anything. Mercedes had these potions, and I took two of them.”

“Incredible! You must ask her to let me study them sometime, Annette. I would be in your debt.”

“Hmm…”

“Actually, let me do you a favor before asking one of you. Come to my room, you can borrow some of my clothes. They should fit you… heightwise, at least. I can’t say I have anything like your figure. Tomorrow is a free day, I can even run into town and get you some better fitting ones.”

“You would do that for me Linhardt? That’s so sweet!”

“Well, I wouldn’t mind you putting in a good word to Mercedes for me. Come on.”

Annette followed him towards his dormitory in silence. A cold wind blew and she shivered, hoping he would offer her his coat. Linhardt had always confused her. And driven her out of her mind, and sometimes made her laugh… His reaction to Annette’s body left her miffed. He was clearly impressed by the changes, but it seemed in a more academic sense, and less in the…

It wasn’t that she really  _ wanted _ to be ogled at, but maybe something a little less detached? 

She almost stopped in time as Linhardt stopped to unlock his door. Her breasts pressed into his back before she took a mortified jump backwards, unused to how far they went out in front of her. Linhardt turned around, suddenly looking somewhat flushed himself.

“Sorry about that. This is the place.’

He seemed to fumble with the key a little bit as he opened the door, and Annette was suddenly stuck with a very Mercedes thoughtwave, resolving to see what Lindhardt really thought about her new body. 

“Thanks so much Linhardt, you’re a lifesaver!” She said with a grin, jumping up and down with excitement. This was a cheap trick, and very much unlike her, but she definitely saw his eyes track down to her bouncing breasts. When he noticed that she was watching his eyes, he flushed deep red and turned away. Not so aloof after all!

“Er, really it’s nothing… Here, let me get you some clothes, and you can be on your way.” He quickly rifled through his drawers until he found some underwear and pajamas and tossed them to her without turning her way.

Normally, Annette would have been scandalized at the very thought of wearing a fellow student’s clothes — especially a boy’s, and especially his. But things were a bit desperate, and she was breaking all the rules anyway. 

“You’re the best, Linhardt.” Annette turned around and took off the bathrobe, putting on his underwear. It was surprisingly tight, and she had to wiggle her hips back and forth to inch it over her round ass. The shirt was fairly loose, but most of the material hung over her chest, leaving part of her stomach exposed. Despite the loose fit, Annette was still visibly poking through. The pants barely fit at all, as Annette’s thighs were much bigger than Linhardt’s, and the material stretched as she forced it on.

“How do I look?” She asked.

“I think I wear it better,” Linhardt said as he finally turned to face her. “But... not bad.” He offered her a shy smile, the detached bravado from earlier almost completely gone. Annette returned it wholeheartedly. They usually fought, but for him to go out of his way to help her like this really was nice. She supposed they were friends after all...

“Well, it actually was somewhat entertaining to run into you tonight, but I do have a date at the library tonight.”

“What, really?”

“Figuratively, of course. I’ll be reading a book.”

“Oh — well, thanks again for everything. I should get back to my dorm then.”

“I’ll see you tomorrow, I guess. When I bring your clothes.”

“Yeah! Wait, you’ll need my measurements, won’t you?”

“Measurements?” Linhardt looked like he’d never heard the word before.

“Yeah, like… you know. Height. And other... stuff...” Annette found herself wishing she’d never brought the subject up. “You know what, forget I said anything. I can figure out the clothes situation tomorrow.”

“No, a promise is a promise. Just tell me your measurements, I promise not to use them for evil.”

“Well, I don’t exactly know them…”

“Aren’t you supposed to know that as a girl? Don’t girls know those things?”

Annette looked down at her ample chest.

“Oh… right. I guess we could measure everything now.” He got a tape measure from his desk and measured her height. Then he stood there and sucked in his breath. “Maybe I’m not the right person to do this. I’d have to, er, get in close.”

Annette felt a bubbliness in her stomach. She suddenly wanted him close. This wasn’t the pure carnal hunger she felt at Mercie’s — well, that feeling was there, but there was something more too.

“I promise I won’t mind.”

She guided him around her body, leading his hands and the tape measure around her generous proportions, going up as they did so.

“It might be easier if I took this off,” she said when they reached her waist. “Do you mind?”

“Not… Not at all.”

She pulled off the shirt and exhaled, leaving her chest bare for him. Linhardt took in a sharp breath.

“What is it?”

“I didn’t say this before, but you really look amazing, Annette. Not that you weren’t attractive before, I mean. Because you were, I just never—”

She kissed him.

It was a quick kiss, and she backed away to view his reaction.

Shock would be the word to describe it. He blinked twice.

“I’m sorry,” she blurted out. “It’s been a really crazy night and normally I would never do something like that, but I’ve just been doing all these new things and it felt right but I shouldn’t have —”

It was his turn to interrupt her. 

“It’s okay.” He moved towards her, getting close together. “I enjoyed it. Not that I’ve ever kissed someone before, so I guess I don’t really know how good it was.”

“I’ve never kissed a boy before either. Maybe we can try again?”

It was his turn to kiss her, then her him. One at a time, at first, then they began in earnest. His hands rested awkwardly on her shoulders, and she guided one of them to the nape of her neck, and the other to her lower back.

They pressed closer together, and Annette felt Linhardt lace his fingers into her headband pulled her face even closer. She did the same to him, and felt a familiar heat rising in her groin. 

Pulling back, she began fumbling with his coat. After a moment, he caught on and was soon bare-chested. She pressed her skin to his and ran her mouth along his neck, pressing in here and there as she made her way to his ear.

“You can put your hands wherever you want,” she murmured.

Linhardt brought his shaking hand up along her body, brushing against the bottom of her right breast. It was the faintest touch, but her melon sized breasts were hypersensitive to the slightest touch, and she let out a sharp breath.

Moving more confidently, he brushed the front of her breast again before bringing his hand in and exploring the considerable shape and size. He gave a quick squeeze and she moaned in his ear, eyes closed and mouth open as she rode the wave of intense pleasure. Such sensation from only the slightest of touches!

“Is that good?” he asked.

“Keep going.”

Linhardt brought his other hand down and did the same, squeezing and playing with her breasts, and Annette loudly gasped, a spasm riding through her body. She tightly gripped his back and squeezed with her hands, trying to make sense of the sensation. Her legs were tightly wrapped around him, and she felt the bulge in his pants rub up against her. She began grinding against it, trying to satisfy the feeling she felt.

Linhardt responded by squeezing and playing with more intensity and confidence. He pinched one of her nipples and she screamed, her body roiling and clenching uncontrollably. He continued, and Annette began panting with the exertion of her body.

Linhardt began to guide her to the bed, and in the brief respite of sensation she pushed him down on it. Already, the flexing and motion of her thick thighs had made tears in the borrowed pants. She began shredding them off in a frenzy, and Linhardt followed with his own pants. He stared up at her, naked and on his back, and she straddled his pelvis with her thighs, grinding her plush ass over him, back and forth, her powerful muscles letting her move like she never had before. As she grinded, her huge tits bounced up and down, and Linhardt brought his hands up to pleasure them again.

She needed more.

She reached her hands down and held Linhardt steady as she edged herself forward. Linhardt followed her lead and slowly fit himself into her.

It was painful, and yet the sensation was unlike anything else.

“Keep going, Linhardt.”

She began to grind again as he thrusted in and out, even as his hands squeezed and pinched and fondled her massive bouncing breasts. She clenched her thighs tighter around his pelvis with powerful muscles that could crush a watermelon as she rode him back and forth, rocking and riding the waves of pleasure. 

He thrusted harder, going deeper than Annette had thought possible, and as before with Mercedes the feeling overwhelmed her.

She screamed his name, tongue hanging out and eyes screwed up as her head rocked with each powerful thrust that rippled through her augmented body

“Linhardt! Don’t stop. Don’t stop!

“I hope you’re as glad as I am that I washed my spare set of sheets yesterday instead of putting it off.”

Linhardt’s bed was something to be envied. Huge and feather soft. Snug sheets and warm, cozy blankets. Huge, fluffy, inviting pillows. The boy took his sleep seriously. 

“I’m usually quite protective of my sleep time. I didn’t think I’d be sharing this bed with anyone when I first got here,” he said, shifting in the sheets to look at her. In the dark Annette could just barely make out a wink.

“Goodnight, Linhardt.”

It’d been quite a night. Annette did not expect when she knocked on Mercedes’ door that she’d be ending her night in a boy’s bed, let alone Linhardt’s. She suspected things were going to get pretty crazy when the morning came, and news spread. But the morning was a ways away, and now was the time to rest.

Annette’s hand cast around for his, and the two held hands as they drifted off to sleep.

**Notes for the Chapter:**

> My original plan had something involving Ingrid, but as I wrote the scene of Annette making her way back to her room and reflecting on recent events, this chapter grew organically out of it. Linhardt is one of my favorite characters along with Annette, and I think their supports are way underrated. This chapter took a step much closer towards romance than the original sex fic I started writing, which took me aback, but I don't have a hard and set rule for how this series will go, and I'm happy with how it turned out. I hope you enjoyed reading it as much as I enjoyed writing it!
> 
> Don't want to make any promises on timing but part 3 with more of the Blue Lions should be on its way sometime soon. I still plan on bringing Ingrid in soon - are there any other characters/things you'd like to see in an upcoming chapter?


	3. Ingrid Fixes Her Strength Growth

**Summary for the Chapter:**

> Shocked at the sudden changes in Annette and Mercedes, the third blue lion lady gets a taste of Mercedes' potion.

The day off on Sunday was a blessing. Annette spent the morning holed up in Linhardt’s room, wrapped in a towel, until he returned with a knock.

“Am I good to come in? Are you decent?”

The towel was most certainly not decent, but Annette said yes anyway.

Linhardt opened the door and quickly closed it behind him, presenting her with the folded clothes with a flourish.

“As promised,” he said. “A properly fitted school uniform.”

“You don’t know how much you saved me here, Linhardt.”

“Oh, I have a bit of an idea.”

“Is there any way I can make it up to you?”

“Well… I’d like to think we’ll hang out again sometime. That is, when I’m not reading or napping.”

Annette gave him a warm grin.

“Of course! I’d love that.”

The two smiled at each other for a moment, both unsure how to proceed. Then Linhardt coughed.

“So… your clothes.”

“Oh, right. Can I use your bathroom? Not that you haven’t seen everything...”

The clothes fit well, though they were a bit showier than what Annette was used to. The skirt was a high cut, covering only the very top of her thighs, though she was wearing leggings instead of showing off her bare legs. The material tapered to her waist and hips, leaving little of her figure to the imagination, and there would be no covering up her chest. 

Annette unbuttoned the top button on her uniform the way Dorothea wore it. If she were going to do this, she might as well own it.

“How do I look?” she asked, stepping back into Linhardt’s dorm. She struck what she thought was a seductive pose, sticking out one leg and popping out her hip, but burst into laughter right away.

“You look amazing, obviously.” Linhardt cracked a smile despite himself at her goofiness. “What’ll you do now?”

“Meet Mercedes and Ingrid, I think. I’m gonna have a lot of explaining to do.”

“Yeah… see you around, then?

“See you around.”

.........

Annette made her way to the usual spot at the dining hall, taking note of the shocked stares — very interested stares, from some of the boys — of her classmates as she walked. Part of her wanted to shrink away from the attention, but a new, growing part of her relished in it. She took her meal and sat down next to Mercedes, who had also managed to find a better-fitting uniform. It showed little skin, but like Annette’s, wrapped tight around her bust and figure, showing the transformation off for all to see.

“Morning Annie. Had an interesting night?” she said with a wink.

“Yes! Mercie, I have to tell you who I ran into!”

Mercedes grinned and put a hand over her mouth. 

“Was it a boy? And here I thought I’d have you all to myself!”

“Annette, Mercedes!” Ingrid ran up to them, breathless. “People have been talking about you. What’s going on…”

She lost her train of thought as her eyes traced over their bodies. Her cheeks flushed red.

“What happened? You two look so - so womanly!

“Mercedes gave me —” Annette began

“Not here, there are eavesdroppers!” Mercedes said conspiratorially, looking around at the various students watching them. Let’s meet in your dorm, Ingrid. We’ll tell you everything.”

“Yeah, let’s do that,” Ingrid agreed. The three stood up and headed to the exit. Sylvain was there, waiting for them.

“Hi Sylvain, we were just leaving,” Ingrid said.

“Oh, hey,” Sylvain said with little interest to her. He only had eyes on Mercedes and Annette. “And hello.”

Mercedes giggled.

“Hi Sylvain. What’re you up to?”

“I wanted to ask you the same thing.”

“Oh, just an ordinary day for me.”

“You’re gonna be coy about it? Well then, I’d love to hear about your day sometime. You can tell me all about it — how about over dinner ton-”

Ingrid whacked him on the head.

“We’re busy, Sylvain,” she said thunderously. “Come on, let’s go.” She grabbed Mercedes by the hand and practically dragged her away.

This was awkward.

“Hey, talk to you soon, okay?” Sylvain looked like he wanted to follow them, but a murderous look from his childhood friend kept him at bay.

Mercedes giggled. She was such a tease!

Ingrid dragged them through Garreg Mach, past all sorts of stares and calls to talk from classmates. Once they were inside, she turned to Mercedes.

“Explain.”

“Of course, Ingrid. I brought some sweets along though — would you like some?”

Mercedes produced a basket with several freshly baked cookies. The aroma was so enticing!

Never one capable of resisting the temptation of food, Ingrid reached into the basket and promptly scarfed down one of the cookies.

“Good?” Mercedes asked.

“Mmmphhh,” Ingrid replied, already stuffing her face with more cookies.

Annette, herself a sweet connoisseur, reached for the basket, but Mercedes swatted her hand away and shot her a look.

Understanding dawned on Annette as Ingrid finished her third. What was Mercedes doing?

“Um, Ingrid, you might not want to…”

“Hm?” Ingrid already had a fourth in her mouth. “These are so good ingrid, I could eat them all day.” She swallowed the cookie after barely chewing it.

Ingrid reached for another, then paused.

“That’s strange… I feel weird now… Was something wrong with them?” Ingrid said, looking confused. Then she jumped straight up. “The cookies — what did you?”

She doubled over, shooting up in height as her legs lengthened.

“Goddess, what’s happening to me?”

Mercedes clapped her hands together, beaming. Annette could only stand there and watch, unsure of the ethics of what had just happened.

Ingrid was quickly filling out her uniform as she grew and changed from the power of the potion-spiked cookies. Her blue leggings stretched and ripped as her legs transformed from skinny to curvaceous and powerful. Ingrid ran her hands down her thighs, feeling the contours and muscle of her thickening legs. Understanding filled her and she stared at Mercedes in shock.

“You - ohhhhhhh.”

Her indignant cry turned into an involuntary pleasured moan as her hips flared out and her legs continued to grow. Long tears formed in the seams of her leggings, exposing the flesh of her legs. Her hands then shot to her butt as it took its turn to grow.

Ingrid closed her eyes and moaned deeply, the experience clearly intensely pleasurable. One hand shot to her groin as the other felt around her growing ass. She stood up, her lower body still developing. Annette didn’t know how much potion was in each cookie, but Ingrid seemed to have taken a megadose of the stuff.

She shot up another few inches, rising above Annette and Mercedes as her skirt covered less and less of her growing thighs, hips, and ass. Ingrid stamped her feed and rubbed her legs together as her lower body continued to grow. They were somehow even shaplier, more majestic than that of Annette’s, and showed no sign of stopping.

The potion had begun to move to Ingrid’s upper body, and she buckled and convulsed as her waist tapered in and her breasts ballooned out.

“Yes… Yes!”

Ingrid squeezed and hugged her expanding tits, which were now pushing her bra and uniform to the absolute limit — and soon went beyond that. Her moans of pleasure turned to one of pain, and she ripped at the uniform, tearing the fabric open, her mind too clouded with sensation to think of unbuttoning the shirt.

The fabric, already under assault by Ingrid’s ever-growing tits, came apart easily at her struggle, and soon the flesh of Ingrid’s tits came into view. They were enormous, bigger than Annette’s and Mercedes’, and continued to grow larger. Ingrid kept ripping at her shirt, and under pressure from both Ingrid and her expanding tits, the fabric ripped further along the existing tears, leaving Ingrid’s upper body and bare tits exposed.

Free of her constraining bra, Ingrid cupped and squeezed her massive tits in each hand, moaning and heaving.

“More! More! Bigger!” she said, face screwed up in pleasure. She now towered above them, a bit over six feet tall, and her tits were the size of watermelons. They sat perkily on her chest, each one larger than her head, bouncy, perky, huge. Sitting side by side, they were as wide across as her shoulders, spilling off her chest. Annette watched in awe.

Ingrid’s growth began to slow as she worked her way out of her shredded clothes to stand naked before the two of them. As more of her exposed body came into view, Annette appreciated the lean muscle Ingrid had on her body, and how the potion seemed to be enhancing it. She wasn’t ripped by any means, not underneath all of her curves, but even they couldn’t hide the muscles on her legs, arms, and abs. The potion had given Annette a pair of thick, powerful legs, but it hadn’t developed her upper body in the same way at all.

Annette had already considered Ingrid to be extremely beautiful, now she looked like some kind of fertility goddess. Her skin looked clearer and seemed to shine. Even her thick, lustrous hair had grown even longer and stronger, and seemed to shine a purer color of gold. Annette wanted to take more of the potion to catch up with her, but knew she could never compare to Ingrid’s ravishing beauty, which the excess potion had enhanced thousandfold.

Ingrid finally stopped growing. She stood in front of them, her shoulders as high up as their heads, her body far more defined and womanly. Her chest heaved from the strain of the growth, her enormous breasts rising and falling with each heavy breath. With her hands, she was exploring every line and contour of her new body, gasping slightly when she passed over a sensitive part. She didn’t seem to register the other two as even being there.

Mercedes broke her stupor by taking her hand and leading her to a mirror.

“Well, what do you think?”

Ingrid’s mouth fell agape. If she had been shocked during the transformation process, this was nothing compared to seeing herself for the first time.

“Goddess,” she breathed. “I look… These are so…” She gestured at her massive breasts, turning to see how far they extended out in her profile.

“Mercedes!” Annete said, suddenly angry. “You should have asked her if she wanted to do this, not trick her into it! Ingrid wants to become a knight, how is she supposed to do that with, well - those! How is her back going to support those?”

“No, it’s fine,” Ingrid said. “Great, actually. I feel great. I know that my breasts are heavy, but strangely I don’t seem to feel the weight. In fact, I feel so… powerful now. So strong.”

Ingrid walked over to a training lance leaning against the wall, and her step was sensual elegance, her legs and hips moving with a grace that seemed both natural and precise. She picked up the lance and spun it around with one hand.

“Amazing,” she said. “This feels like nothing.” She turned to a dresser and lifted it like it was nothing as well. “I could take on an entire army by myself! Mercedes, thank you.”

Mercedes clapped her hands together, endlessly pleased with herself.

“Of course, Ingrid! You can repay me by giving me a twirl!”

“Oh, um. Sure.” 

Ingrid spun around, and Annette and Mercedes clapped. Ingrid blushed and gave a mock curtsy.

“You’re so pretty! If you could just let me put some makeup on you now…”

“I think this will turn enough heads on its own. Do you have anything I can wear that will fit now?”

“I hope you have a big bathrobe,” Annete said.

“Well, find me something. I need to try this body out!

.........

An hour or so later, the three of them headed down to the training grounds. Ingrid was wearing a large male uniform, which hid the curves on her waist but did little to bely the changes to her chest, hips, and thighs. If people had been curious before, they were positively abuzz after seeing the changes Ingrid had gone through since the morning.

Ingrid didn’t notice any of it, so focused was she on testing the limits of her enhanced body. Soon they had arrived, and she wasted no time in finding the heaviest looking axe she could find.

Lifting it as though it were no heavier than a dinner plate, she swung ferociously at a training dummy, sinking the axe deep into it with a single swing.

“Ha!” she said, with a ferocious grin, swinging again, then twice more, until she cleaved straight through the dummy.

A small crowd had gathered to watch. Felix, clearly impressed more by Ingrid’s power than her melon-sized breasts, set up a series of training dummies in the center of the training pit. Ingrid found herself another equally-sized axe and held on in each hand before savagely pouncing from dummy to dummy, cutting each one to pieces with wild strokes.

The exertions had more of an effect on Ingrid’s clothes than her. Halfway through the exercise, her pants tore along the side of thighs as the muscle bulged out, too small and weak to contain the flexing of her powerful thighs. The top two buttons of her uniform, already too tight across her chest, flew off as well.

Ingrid took little notice. Dropping one axe, she gripped the other with both hands as she left six feet into the air, bringing the axe head down on the last dummy and cleaving it in two along the center. Her uniform ripped open along her upper back, revealing a set of powerful back muscles rippling from the exertion.

Picking up the other axe, Ingrid turned to face the crowd. Her torn uniform revealed a powerful body glistening with sweat. Her long hair was wild, and a savage gleam colored Ingrid’s eyes as she surveyed them.

“Anyone want to spar?” she asked.

**Notes for the Chapter:**

> I have fun writing these on the side, so thank you to everyone that has read all three entries so far. I don't have a specific plan in mind for where I want this to go, but as long as it's enjoyable to read and write then I'm not too worried about it. Muscle growth is also something I'm a fan of, and Ingrid seemed like the character to start that kind of stuff with. I'll definitely do more with that in further chapters, though a POV switch might be necessary, as having everything happen from Annette's point of view is getting limiting. A commenter requested something with Dimitri and Marianne, two of my favorite characters, so you might be seeing some of them soon.
> 
> Thanks again, and I hope your 2020 ends better than it started.


	4. Tough Times for the Tested Professor

**Summary for the Chapter:**

> Byleth struggles to keep his class in order as a new student - and some changes in his old students - cause mayhem in the classroom. He tasks Dimitri with getting to the bottom of the situation.

“Roll call,” Byleth said, eyeing the transfer paperwork. Having no prior experience with teaching, roll call was one of the many pedagogical rituals the professor routinely skipped. But there was a transfer student joining today, and he figured he might as well pretend the Blue Lions had a qualified teacher leading them. At least until the first impression phase was over.

“Felix?”

“Present.” Felix was sharpening a sword, ignoring the looks of alarm from the new student.

“Ashe?”

“Present, professor!” Ashe sat ramrod straight, eager to learn. Maybe too eager…

“Mercedes?”

“Here I am, professor!” Mercedes looked quite different.

“Anne-” Byleth put down the paperwork and went in for a second look at Mercedes. She looked quite different. Mercedes caught him looking and beamed knowingly, so Byleth quickly shifted his gaze away. Ashe was sitting in the seat next to her, and seemed to be making a pointed effort to focus on his books and not her giant breasts.

Byleth shook his head.

“Annette?”

“Here!” Byleth avoided staring too much upon noticing she had undergone a similar, but far more drastic, change as Mercedes.

“Dimitri?”

“I am here, professor.” Dimitri was also making a point to look anywhere but in his female classmates’ general direction.

“Dedue?”

“Here.” As was Dedue.

“Marianne?”

“...I’m here, professor.” The quiet girl from the Yellow Deer house had requested to transfer to Byleth’s class on Friday, and he’d gotten the paperwork sorted out for today. She seemed sweet, but he wasn’t sure why she would want to join. They’d had brief conversations, but she hadn’t seemed too interested in talking.

“Sylvain?”

“Here, professor.” Sylvain had his feet propped up on the desk and arms folded behind his head, leaning his chair back on its two legs, the very definition of nonchalant. “Ingrid isn’t here yet, but I’m saving her seat.”  
Ingrid had indeed not arrived, but the only spare desk was on the other side of the room. Byleth walked over to the amorous student.

“What seat would you be saving for her?”

Sylvain looked up at his professor with an impish grin and patted his lap. Marianne, who was in the seat next to his, looked mortified and buried her face in her book. Sylvain’s grin was broken by Byleth smacking him on the head with his pointing stick.

“Ow!”

“Unless we’d like to discuss any other nonsense,” Byleth said, addressing the rest of his house. “You may have noticed a new student in our midst. I’d like to introduce you to the newest Blue Lion.”  
Ingrid chose that moment to burst into the room.

“I’m so sorry, professor! I got caught up in training this morning.”

She did not appear to be lying. Her outfit consisted of a skirt and boots without the usual leggings, and the white button-up that was part of her uniform - sans the sleeves and a few buttons. This emphasized that she was not only covered in a sheen of sweat, but looked as though she’d been training her body every day… for the last several years. Every exposed bit of skin rippled with muscle

Not to mention the other changes to her physique, which made Annette and Mercedes look tame in comparison.

“Ingrid!” Mercedes said. “I see you’ve been training since I last saw you. You’re even bigger than you were before!”

“She’s been at it all night, as far as I know.” said Felix. “She was still going at it even when I got tired and left the training grounds.”

Ingrid flushed and rubbed her bicep.

“I may have lost track of time. I still don’t quite feel tired.”

“You should see her in action, professor. I don’t know what’s with the weird boob potion they’ve been sharing with each other, but it made her stronger than a crest beast.” Felix looked thoughtful and turned to Annette and Mercedes. “You two should stop by the training ground later.”

Byleth saw Sylvain about to rattle off a line and decided now was the time to regain order.

“Settle down. As I was saying, we have a new Blue Lion joining us today...

After making introductions, Byleth led them to a training field, where he had them pair off for individual sparring sessions before he put them into a larger group for a mock battle with Alois, Catherine, and a few other Knights of Seiros. The idea was to get  
Marianne integrated into the group and have them working as a team. As it stood, he might have some issues getting past the first part of his lesson plan.

Ashe and Dedue had both paired off and were in an intense sparring session, both terrified of letting their attention wander enough for them to ogle the newfound busts (and butts) of their female classmates. This was fine by him, but the others…  
Felix was chasing around a terrified Annette, convinced she was hiding a newfound strength from him. She, from the looks of it, did not have the increased muscle power of Ingrid, and in fact had spent more time falling off balance and eating dirt - most likely due to the new weight on her chest. Her uniform seemed ill small for this kind of… movement, as several chest buttons had already popped off.

Byleth caught himself staring more than he considered appropriate and moved his attention to the next group.

Marianne and Mercedes had done little actual sparring, mostly because Mercedes had been trying to get the blue-haired girl to come out of her shell. This was well enough, but she seemed utterly terrified of her sparring partner and would offer barely-audible responses. He would step in, but he had to keep a close eye on Ingrid to keep her from straight-up killing Sylvain.

Sylvain had immediately offered to be Ingrid’s sparring partner, and she accepted - likely because she’d have the opportunity to wail on him with her new strength. Felix had been right; her strength was something to behold, and even her newly muscular frame didn’t seem to truly represent her power. She’d already shattered two sets of training swords and three of Sylvain’s shields. As it didn’t seem possible for her to swing a weapon without maiming Sylvain, Byleth had told them to train without them. Ingrid immediately suggested wrestling: The result was her pinning Sylvain to the ground with ease, over and over, in every position imaginable, sometimes with one or both hands tied behind her back. Ingrid never seemed to tire from the exertions. Her muscles actually seemed to be growing larger and more defined as she grappled Sylvain.

As Sylvain struggled against the bulging thighs Ingrid had wrapped around him, Byleth wondered what was going through his head: whether he wanted the public embarrassment of being trivially overpowered by a girl in front of his peers and friends to end, or if getting to grope a busty amazon was an experience he never wanted to end. Probably both, but more of the latter, if Byleth had to guess.

Byleth himself was training with Dimitri, but they had to break often so he could try to get his students to stop acting like animals.

“I apologize for my classmates, professor,” Dimitri said after Byleth told off Felix for the third time.

“I’m not setting a very good example,”

“As house leader, it is I that should be setting a better example. But the cause of today’s chaos seems to be… the differences in… don’t make me say it.”

Byleth stared at him.

“Ah, curse you professor!” A mortified Dimitri mimed the outline of breasts. “I am not sure what happened to Annette and Mercedes, nor the cause of Ingrid’s bloodlust.”

“Have you heard anything from the other students?”

Dimitri looked behind him to check if anyone was listening in.

“Mercedes and Annette changed overnight. Sylvain would not shut his mouth about it. Ingrid looked normal yesterday, but I saw the two of them leading her somewhere as well, so it seems they’ve been using some sort of magic to…” Dimitri coughed. “Change their bodies.”

Byleth thought for a moment.

“Professor?”

“As house leader, I need you to do something for me.”

“Of course.”

“Talk to them and find what kind of magic they’re using. Possibly when they give it to Marianne as a welcoming gift. Ingrid is more muscular every time I check on her - think of the potential to increase everyone’s strength”  
Dimitri blanched.

“I need a man I can trust. Think of the potential in battle,” Byleth said, putting a hand on his shoulder. “There’s also no way I can go near this myself.”

Dimitri closed his eyes, as if hoping this were a bad dream he could wake from. The boy was fearless in battle, but hopeless when it came to the subject of girls. This was cruel, but Byleth would force him to learn. A king must be strong.

When Dimitri opened his eyes he saw the absurd but all-too-real sight of Ingrid crushing the life out of Sylvain for copping a feel in their latest bout.

“Very well, professor. Please honor my memory if I don’t return.”

**Notes for the Chapter:**

> Happy New Year! I had some fun this chapter introducing the rest of the Blue Lions to the story and starting some new plot threads. They're easily my favorite house and it'll be nice to have them in the mix... assuming Ingrid doesn't suffocate Sylvain between her thighs before the next chapter. This series recently hit 1,000 views, which isn't a lot by any means, but it's really big to me. Tune in next update to see if Dimitri survives his mission.


End file.
